This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-244603, filed Aug. 10, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a vertical chemical vapor deposition system. In particular, the present invention relates to a device for improving the temperature distribution within a susceptor in a vertical chemical vapor deposition system.
2. Description of the Related Art
In a conventional vertical chemical vapor deposition system, the operators have measured the surface temperature of the susceptor and the surface temperature of wafers placed on the susceptor in the following manner. That is, the operators have set a measuring point by a radiation thermometer to a target position while viewing inside of a reaction chamber form a view port provided at a ceiling of the reaction chamber. As described above, in order to visibly reconfirm the measuring point, the operators must look into the reaction chamber, which is in a high temperature state. For this reason, there is a problem relevant to the operation in the conventional vertical chemical vapor deposition system. In addition, it is not always easy to accurately set the measuring point to the target position; for this reason, there is a problem that the position on the measuring point is subtly different depending on the operators.
In a vertical chemical vapor deposition system, generally, the susceptor is heated by an induction heating coil arranged below the susceptor. The temperature distribution within the surface of the susceptor is adjusted, in a step of assembling, by setting the heights of several parts of the coil manually. However, it takes long time to adjust the heights manually, and it is not easy to get uniform temperature distribution within the surface of the susceptor.
The present invention has been made in order to solve the above problems arisen when measuring the surface temperature of the susceptor and wafers in the reaction chamber and arisen when controlling temperature distribution within the surface of the susceptor. Accordingly, it is an object of the present invention to provide a vertical chemical vapor deposition system, which can measure the surface temperature of the susceptor and wafers in the reaction chamber accurately and improve temperature distribution within the surface of the susceptor.
According to the present invention, there is provided a vertical chemical vapor deposition system comprising:
a reaction chamber comprising a base and a bell jar;
a susceptor arranged in the reaction chamber;
an induction heating coil arranged below the susceptor, and heating wafers placed on the susceptor;
a height adjusting device for supporting the induction heating coil and adjusting a distance between the susceptor and at least a part of the coil;
an observation port provided in the bell jar;
a radiation thermometer arranged outside the observation port, and measuring a surface temperature of the susceptor and the wafers placed on the susceptor;
a drive mechanism supporting the radiation thermometer, and moving a measuring point by the radiation thermometer in a radial direction of the susceptor; and
a control unit controlling the drive mechanism, and sequentially setting the measuring point by the radiation thermometer to preset positions so that an output of the radiation thermometer at each measuring point can be captured, and controlling the height adjusting device so that the output of the radiation thermometer coincides with a predetermined value.
In the vertical chemical vapor deposition system of the present invention, the movement of the drive mechanism and the capture timing of the output of the radiation thermometer interlocking therewith are previously set to the control unit. By doing so, it is possible to automatically perform the position setup of the measuring points by the radiation thermometer and the capture of the output from the radiation thermometer without doing a manual work by the operators. By adjusting the heights of parts of the induction heating coil based on the temperature distribution thus acquired, it is possible to get uniform temperature distribution within the surface of the susceptor accurately and automatically without doing manual work by the operator.